SYNOPSIS

DESCRIPTION

Verifies the connectivity and validity of the objects in the database.

OPTIONS

<object>

An object to treat as the head of an unreachability trace.

If no objects are given, git fsck defaults to using the
index file, all SHA1 references in .git/refs/*, and all reflogs (unless
--no-reflogs is given) as heads.

--unreachable

Print out objects that exist but that aren’t reachable from any
of the reference nodes.

--dangling

--no-dangling

Print objects that exist but that are never directly used (default).
--no-dangling can be used to omit this information from the output.

--root

Report root nodes.

--tags

Report tags.

--cache

Consider any object recorded in the index also as a head node for
an unreachability trace.

--no-reflogs

Do not consider commits that are referenced only by an
entry in a reflog to be reachable. This option is meant
only to search for commits that used to be in a ref, but
now aren’t, but are still in that corresponding reflog.

--full

Check not just objects in GIT_OBJECT_DIRECTORY
($GIT_DIR/objects), but also the ones found in alternate
object pools listed in GIT_ALTERNATE_OBJECT_DIRECTORIES
or $GIT_DIR/objects/info/alternates,
and in packed git archives found in $GIT_DIR/objects/pack
and corresponding pack subdirectories in alternate
object pools. This is now default; you can turn it off
with --no-full.

--strict

Enable more strict checking, namely to catch a file mode
recorded with g+w bit set, which was created by older
versions of git. Existing repositories, including the
Linux kernel, git itself, and sparse repository have old
objects that triggers this check, but it is recommended
to check new projects with this flag.

--verbose

Be chatty.

--lost-found

Write dangling objects into .git/lost-found/commit/ or
.git/lost-found/other/, depending on type. If the object is
a blob, the contents are written into the file, rather than
its object name.

--progress

--no-progress

Progress status is reported on the standard error stream by
default when it is attached to a terminal, unless
--no-progress or --verbose is specified. --progress forces
progress status even if the standard error stream is not
directed to a terminal.

DISCUSSION

git-fsck tests SHA1 and general object sanity, and it does full tracking
of the resulting reachability and everything else. It prints out any
corruption it finds (missing or bad objects), and if you use the
--unreachable flag it will also print out objects that exist but that
aren’t reachable from any of the specified head nodes (or the default
set, as mentioned above).

Any corrupt objects you will have to find in backups or other archives
(i.e., you can just remove them and do an rsync with some other site in
the hopes that somebody else has the object you have corrupted).

Extracted Diagnostics

expect dangling commits - potential heads - due to lack of head information

You haven’t specified any nodes as heads so it won’t be
possible to differentiate between un-parented commits and
root nodes.

missing sha1 directory <dir>

The directory holding the sha1 objects is missing.

unreachable <type> <object>

The <type> object <object>, isn’t actually referred to directly
or indirectly in any of the trees or commits seen. This can
mean that there’s another root node that you’re not specifying
or that the tree is corrupt. If you haven’t missed a root node
then you might as well delete unreachable nodes since they
can’t be used.

missing <type> <object>

The <type> object <object>, is referred to but isn’t present in
the database.

dangling <type> <object>

The <type> object <object>, is present in the database but never
directly used. A dangling commit could be a root node.

sha1 mismatch <object>

The database has an object who’s sha1 doesn’t match the
database value.
This indicates a serious data integrity problem.